Supplementary Figure 2: Deficiency in both TCF-1 and LEF-1 does not affect TCR-dependent induction of the expression of GATA-3 and Tox.

Although CD69 expression was reduced in TCRβ^hi thymocytes from Tcf7^-/-Lef1^-/- mice (Fig. 1c), the combination of CD69 and CD24 was sufficient to distinguish immature and mature subsets within the TCRβ^hi population. The surface-stained thymocytes from Tcf7^-/-Lef1^-/- and littermate controls were sorted for 3 subsets, pre-select DP (PreDP), post-select DP (PostDP), and CD4⁺8^lo intermediate (IM). Gata3 and Tox expression was measured as an end outcome of TCR signaling in positively selected DP subsets. The relative expression of each gene was normalized to Hprt1. Data are pooled results from 3 independent experiments and shown as means ± s.d. (n ≥ 3). Gata3 and Tox expression between control and Tcf7^-/-Lef1^-/- within each subset was not statistically different (p>0.4). Note that the post-select DP thymocytes from Tcf7^-/-Lef1^-/- mice may contain a fraction of CD8⁺ T cells that had derepressed expression of CD4 (the CD8*4 cells). Because Gata3 and Tox were less abundantly expressed in CD8⁺ T cells compared with DP thymocytes, CD8*4 cells unlikely contributed to elevating Gata3 and Tox expression in Tcf7^-/-Lef1^-/- post-select DP thymocytes.